From U.S. Pat. No. 3,532,038 there is known an optical system in which a transparent base member is provided with lenticular lens cavities, which cavities are filled with a refractive fluid, the surface of which fluid is covered with a cover member. The cover member is provided with an aperture plate, on which finally a second base member is present, which is also provided with lenticular lens cavities, which cavities are likewise filled with a refractive fluid.
From US 2004/0100700 there is known a method of manufacturing a micro lens array, wherein the cavities in a mould are filled with a UV curable resin, whilst the resin outside the cavities is removed by placing a transparent quartz board on top of the mould. The fluid present in the cavities is then formed into a plurality of separate lenses, whereupon a second UV curable resin layer is applied to the transparent board, which resin layer is cured by making use of the already formed separate lenses. The excess amount of the cured second resin layer is removed by using an organic solvent. Only one layer of replicated lenses is mentioned in said document, which lenses are separately arranged and do not exhibit any interconnection.
The replication process is known per se from U.S. Pat. Nos. 4,756,972 and 4,890,905, which disclose the possibility of manufacturing a high-quality optical component by means of a replication process. Such a replication process is considered to be a quick and inexpensive manner of manufacturing optical components in large numbers. In the replication process, a mould having a precisely defined surface, for example an aspherical surface, is used, and a small amount of a radiation curable resin, for example a UV curable resin, is applied to the mould surface. Subsequently, the resin is spread over the mould surface, so that the cavities in the mould are filled with the resin, after which the whole is irradiated so as to cure the resin and the thus cured product is removed from the mould. The cured product is a negative of the mould surface. An advantage of the replication process is that lenses having a complex refractive surface, such as an aspherical surface, can be manufactured in a simple manner without having to subject the lens body to intricate grinding and polishing processes.
From International application WO 03/069740 in the name of the present applicant there is also known a replication process by which an optical element is formed.
WO 2012100356 relates to a method for manufacturing a plurality of optical devices, comprising the steps of: providing a replication tool, the replication tool comprising a replication surface defining an array of replication cells, each replication cell comprising a lens replication portion and a spacer replication portion, bringing the replication tool and a support in contact with each other with replication material between the replication surface and the support; causing the replication material to harden, wherein, during the step of causing the replication material to harden, the lens replication sections are caused to be kept at a distance from the support.
US 2009022949 relates to a process for producing a functional-element-mounted module, comprising the steps of disposing a substrate having mounted thereon a functional element having a mounting portion and a resin sealing plate formed therein with an opening corresponding in position to the functional portion of the functional element as opposed to each other at a predetermined distance; and impregnating and filling a sealing resin between the substrate and the resin sealing plate utilizing a capillary phenomenon.
WO 2015093945 in the name of the present applicant relates to a method of fabricating a wafer level optical lens assembly, comprising: providing a first wafer substrate having a plurality of bumps; applying a first polymer liquid on a first contact optical surface of said plurality of bumps; providing a second wafer substrate; contacting said first wafer substrate with said second substrate in such that said first polymer liquid is located in a slit created between said first contact optical surface of said plurality of bumps and said second wafer substrate under capillary forces; curing said polymer liquid(s) to form a lens.
US 2009034088 relates to a method of making a micro-optical device, comprising: providing a replication material between a support substrate and a master substrate having structural features for forming a micro-optical lens, the replication material covering at least a portion of an opaque material on the support substrate; applying pressure to at least one of the support substrate and the master substrate; curing the replication material to form a replica including the micro-optical lens; and removing the support substrate including the opaque material and the replica.
US 2012200943 relates to a method of forming a lens, comprising: molding a pre-final lens using a first master, using a second master to form a top layer atop the pre-final lens, wherein the pre-final lens includes a deformity due to shrinkage of the pre-final lens after molding the pre-final lens, and wherein the top layer substantially corrects the deformity, wherein the pre-final lens forms a majority of a final volume of the lens.
WO 2014092148 relates to a method for manufacturing a lens array structure, whereby an adhesive is applied between first lens elements formed on a lens array and pushing out of the adhesive applied on the periphery of the outside lens elements to the surroundings can be limited.
EP 1 837 165 relates to a method of manufacturing an element by means of a replication tool, comprising the steps of providing a replication tool that defines the shape of the element; providing a substrate; pressing the replication tool against the substrate, with a replication material in a liquid or viscous or plastically deformable state located between the tool and the substrate; confining the replication material to a predetermined area of the substrate, which predetermined area exceeds the desired area of the element on the substrate, in at least one direction along the surface of the substrate by less than a predetermined distance; hardening the replication material to form the element.
From the above state of the art there are thus known methods by which optical systems are obtained which are made up of separately manufactured optical elements, as a result of which the dimensions of such systems may be considered to be large. In addition, the positional accuracy, viz. in the X, Y and Z directions (between the lens surfaces) of such systems may be called critical.
Current controlled contour shapes of optical elements are determined by mold shapes. Toolings for these complex shapes are expensive. Mold surfaces for only optical surfaces need to be very accurately shaped (typical λ/40 or better). Peripheral structures require far lower shape accuracies of at least 100 times lower.